Many conventional imaging devices include a bed on which the patient is placed, a control station suitable to control the functioning of the device, and a gantry, that is, a device having a cavity in which the portion of the patient to be analyzed is inserted and suitable to perform the radiological imaging of the patient.
Inside the gantry, the radiological imaging devices are provided with a source suitable to emit radiation on command, such as X-rays, and a detector suitable to receive the radiation after it has traversed the portion of the patient to be analyzed and to send a signal suitable to permit visualization of the internal anatomy of the patient.
Typically, given the need to visualize extensive parts of the body, the detector used is a flat panel sensor, said flat panel sensor having a particularly extensive detection surface, which in some cases exceeds 1600 cm2.
For example, flat panel sensors may be a direct-conversion type, and include a panel suitable to receive X-rays emitted by the source and to produce a series of electric charges in response, a segmented matrix of TFT in amorphous silicon which receives the aforementioned electric charges, and an electronic reading system. Flat panel sensors also may be an indirect-conversion type, including a layer suitable to receive X-rays emitted by the source and to produce a series of light photons in response (e.g., by scintillation), a segmented matrix of photodetectors (e.g., TFT, CMOS, CCD, and the like) that convert the aforementioned light photons into electric charges, and an electronic reading system. When radiation has struck the entire flat panel sensor, the electronic reading system determines the quantity of electric charge received by each TFT segment in a direct-conversion flat panel sensor or the quantity of electric charge generated by each photodetector of an indirect-conversion type of flat panel sensor, and correspondingly generates a matrix of numbers which represent the digital image.
However, flat panel sensors generally cannot absorb radiation continuously, owing to, for example, the particular interaction between the charges and the segmented matrix of TFT in amorphous silicon. Thus, in order to perform a total body scan of a patient's body, image acquisition of the patient's body is divided into a sequence of two-dimensional images, which are then reconstructed into a total body scan. In particular, reconstruction may require approximating the portions of the body located on edges between two successive images. Furthermore, other portions of the body may have to be reconstructed by approximation of a series of images of those portions. As a result, the use of flat panel sensors in this conventional manner results in poor quality radiological imaging, particularly in the case of total body scanning.
Moreover, the quality of conventional total body scans is also reduced as a result of diffused, so-called parasitic radiation, formed by the interactions between X-rays and matter, which hits the detector and thus degrades the quality of the image. In order to reduce the incidence of parasitic radiation, conventional radiological imaging devices are often fitted with anti-diffusion grids composed of thin lead plates fixedly arranged parallel to each other so as to prevent the diffused rays from reaching the flat panel sensor. However, such grids are only partially effective in remedying the effects of parasitic radiation on image quality. Furthermore, the use of anti-diffusion grids imposes the use of a higher dose, thereby possibly increasing the danger of causing illness.
Additionally, in order to perform different types of analyses to a high standard, a medical center must be equipped with several radiological imaging devices, involving substantial outlays. Moreover, conventional radiological imaging devices are characterized by high production costs and highly complex construction.
Accordingly, there has been a long felt need for a radiological imaging device for performing a total body scan and reconstructing a clear image of a patient's entire body or an extensive portion of a patient's body.